1. Field of the Invention
The present invention relates to a safety door equipped with a safety structure which ensures safety in case a part of an operator's body should be put in an opening when the opening is closed by the safety doors. The present invention further relates to an apparatus, for manufacturing or inspecting semiconductors, having the safety door.
2. Description of the Related Art
When an automatic door opens and closes an opening in a partition wall located between different spaces, there are some risks of catching a part of a person's body, such as fingers or a hand, in the door when the person works around the opening.
For example, in most apparatuses for manufacturing or inspecting semiconductors, an opening is provided on a wall of the apparatus for transferring a wafer from a wafer cassette placed outside into the apparatus. In such the apparatus, an automatic handling robot is used for transferring wafers from the wafer cassette through the opening into the apparatus, and an automatic door for covering the opening is provided at the opening so that it can automatically open and close the opening. An exchange of the wafer cassette placed outside the apparatus is made typically by a person (for example an operator). Therefore, there is some risk of catching a part of the person's body in the automatic door and crushing it during the exchange operation for the wafer cassette.
In order to prevent a person from catching a part of his body in the automatic door, a guard fence for preventing a person approaching is typically provided around the opening or the automatic door. If a person has to work near the opening or the automatic door as in the case mentioned above, it is necessary to take steps to detect a person near the opening or the automatic door by means of an area sensor or the like and thereby to control the operation of the safety door of the apparatus so as to prevent the safety door from closing and opening when some person is near the opening or the automatic door.
However, when the operation of the automatic door is controlled, using sensors such as area sensors, by software of a controller or others, it is possible that an incorrect action may happen in the automatic door due to faults in software or hardware, such as sensors and the controller, and thereby a part of a person's body may be caught in the automatic door.